Fabricated refractory metal firebox



Dec. 19, 1950 c. E. SCHINMAN 2,534,832

FABRICATED REFRACTORY METAL FIREBOX Filed Sept. 20, 1947 2 Sheets-Sheet1 33 20 45 INVENTOR. 34 6%; E. JcH/NMfi/v 52 JTTOBNEYJ 19, 1950 c. E.SCHINMAN 2,534,832

FABRICATED REFRACTORY METAL FIREBOX Filed Sept. 20, 1947 2 Sheets-Sheet2 jQ /QJ 2a 1 30 0- W04 Patented Dec. 19, 1950 FABRICATED REFRACTORYMETAL FIREBOX Carl E. Schinman, Seattle, Wash.

Application September 20, 1947, Serial No. 775,202

2 Claims.

This invention relates to furnaces and it has reference moreparticularly to improvements in firebox construction, and especially tofireboxes as applied to domestic furnaces that are fired with oil bymeans of gun type burners; it being the principal object of thisinvention to provide an improved type of firebox, whereby furnaceheating efiiciency will be materially increased.

More specifically stated, it is the object of my invention to provide anovel firebox structure of stainless steel, designed to receive andshaped to fit the flame from the blast tube of the burner; a fireboxwhich will attain a relatively quick rise to its peak temperature,giving most satisfactory burning operation, the highest heatingefficiency and greatest fuel economy.

It is also an object of the present invention to provide a fireboxstructure that eliminates the need for or use of the usual fire-brick orrefractory linings in firebox chambers, and, in that way, makesavailable the maximum heat radiating surface of the firebox.

Yet another object of my invention is to provide a firebox of stainlesssteel that is made in sections which, when occasion requires it, may bepassed through a furnace door and assembled within the firebox chamberwithhout requiring removal of any parts from the furnace or anyreconstruction or alteration thereof. Furthermore, to provide asectional firebox structure, the parts of which may, if desired, beassembled in part and placed in the furnace firebox through its doorway,for final assembly.

Still further objects of the invention reside in the details ofconstruction of the variou parts embodied in the present fireboxstructure, and in their mode of assembly.

In accomplishing the above mentioned and other objects of the invention,I have provided the improved details of construction, the preferredforms of which are illustrated in the accompanying drawings, whereinFig. 1 is a vertical cross section of the base portion of a domesticfurnace of a typical form of construction, equipped with a stainlesssteel firebox structure, embodied by the present invention.

Fig. 2 is a horizontal section, taken substantially on the line 22 inFig. 1.

Fig. 3 is a cross-sectional detail of the lower end portion of thepresent firebox structure taken on line 3-3 in Fig. 2.

Fig. 4 is a perspective View of the firebox structure, with parts madeand assembled in accordance with the present invention.

Fig. 5 is a longitudinal, sectional detail taken on line 5-5 in Fig. 6,of a part of one of the le members and parts of adjacent wall sectionsof the firebox, as joined and supported thereby.

Fig. 6 is an inside View of the parts as assembled in Fig. 5.

Fig. '7 is an enlarged, horizontal section taken on the line 11 in Fig.6.

Fig. 8 is a detail illustrating the manner of assembling one of the legmembers with hook flanges of adjoining wall sections of the firebox.

Fig. 9 is a horizontal, sectional detail of a front portion of thefirebox.

Referring more in detail to the drawings- In Fig. 1, I have shown thelower portion of a typical form of domestic furnace equipped with afirebox embodied by the present invention. In this view, l0 designatesthe combustion chamber enclosed by the furnace walls or shell ll;entrance to the chamber being through a doorway, as designated at H2 inFig. 1; this doorway being equipped with a door I3.

Within the lower portion of the combustion chamber is located thefirebox embodied by the present invention, designated in its entirety bynumeral l4. Extended horizontally into the furnace through a housing l5applied .to or formed as a part of the front wall of the shell, is theblast tube It of an oil burner designated generally by reference numeral[1.

The present firebox structure [4 is shown best in Figs. 1 and 4 ascomprising a substantially cylindrical housing, of lesser diameter thanthat cylindrical part of the furnace shell in which it is contained.Also, it is shown as being so located in the furnace as to providesubstantial air space between its walls and the shell. The walls of theshell around the firebox are not lined with fire brick as is the usualfirebox, but are exposed to the heat radiating from the firebox. Thepresent firebox is made of stainless steel, or a suitable like material,and is made in sections. It comprises a back section 20, opposite sidesections 2l2l' and a front panel or section 22, all of which parts areindependently formed and are adapted to be assembled in groups or to beapplied individually to the combustion chamber of the furnace throughthe doorway l2 for final assembly within the furnace, as will presentlybe explained.

In the present preferred form of construction, the back section 20comprises a single, rectangular piece of stainless steel plate,uniformly curved between its opposite, vertical side edges, as noted inFig. 2, to conform substantially to the furnace shell curvature, and isformed along the vertical side edges with outwardly and then backwardlyturned hook forming flanges 25. These flanges extend from even with thebottom edge of the plate to just short of the top edge where they arecut ofi at a slight angle, as noted at 25 in Fig. 8.

The opposite side sections 2| and 2| of the firebox are of the sameheight as the back section and, likewise, are made from sheets ofstainless steel, rectangular in form and each formed along its oppositevertical edges with outwardly and backwardly turned flanges or hooks 25like those formed on the back section. These side sections, also, arecurved as noted in Fig. 2 to conform substantially to the cylindricalcurvature of the shell.

The front section or panel 22 comprises a fiat, rectangular plate,somewhat greater in height than the side sections and relatively narrow,as noted in Fig. 4. This plate is formed along its opposite side edgeswith hook-flanges 25 that are outwardly then inwardly turned, like thevertical edge flanges on the back and side sections. These flanges 25 ofplate 22 terminate short of the top edge of the plate and, like those ofthe other plates, are beveled oil at their upper ends, as shown, for apurpose presently understood. Formed in the plate 22, near its lowerend, is a circular opening 23 bounded by an outturned flange 23,designed to receive the blast tube of the burner therethrough as in Fig.2, and at opposite sides of this opening are slots 24-24 for receptionof the burner anchor straps later to be described.

At their lower horizontal edges, the sections 25, 2| and 21, haveinturned horizontal flanges '35 which are best shown in Fig. 3, andsupporte' upon these flanges is a bottom plate 32, of stainless steel,which closes the lower end of the firebox. This plate has an upturnedperipheral flange 33 that fits closely to the sections 28, 21-2!" and22, and the plate operates to a certain extent to establish and maintainthe shape of the housing as it is shown in Fig. 2. The

plate 32 preferably has a circular, downwardly dished portion ofsubstantial 'diameter *as shown in Figs. 1 and to give it rigidity. Whenpressed into place, it is retained by bosses 34 pressed inwardl from theside walls.

The various wall forming sections 26, 2'|--'2|' and 22 which constitutethe firebox structure are supported and also held in their assembledrelationship by four metal legs '49, each of which comprises a straightstrip of metal, with 'opposite longitudinal edge flanges 4'|4| bent backand then toward each other as noted best in Figs. 2, 6 and 8, butleaving open space between the edges of the flanges. The length or theselegs is slightly more than the height of the wall sections and asidefrom serving to join adjacent edges of the sections, they serve also aslegs whereby to support the firebox at a desired elevation above thebottom of the furnace as noted in Fig. 1.

It is to be pointed out also, as a detail of construction thatfacilitates the assembly of the leg portions with the wall sections,that each of the wall sections is formed, parallel with each of its edgeflanges or hooks and spaced slightly therefrom best shown in Figs. 2 and7, with 'an outwardly offset ridge or bead '45. When the flanged edgeportions of two sections are brought properly together for joining, theridges 45 will 'be spaced apart a proper distance to receive a leg 40between them and they operate to some extent in assembly of legs andsections, as guides for directing the lower end of the leg over thebeveled upper ends of the hook flanges 25.

To assemble the parts of the firebox, it is most practical to first jointhe back section 20 and a side section 2| by bringing the hook equippedside edges thereof into proper relationship for joining and to then slipthe lower end portion of one of the leg members 40 into the guidewayprovided by the coacting ridges on the plates as has been illustrated inthe detail of Fig. 8, and then push the leg down over the beveled endsof the hook flanges 25 and down the full length of the flanges until theleg extends the proper supporting distance beyond the lower edges of theplates, for example, as shown in Fig. 6. Then the other side plate isassembled with the back plate, in a like manner, and secured by anotherof the leg members 40. Finally, the front panel 22 is brought intoposition between the forward edges of the opposite side plates 2! and 2|and is secured by the application of the two front leg members so thatthe assembled structure will then appear as shown in Fig. 4.

After the legs have been properly applied and have been extendeddownwardly below the plate edges to the amount required, they may besecured against any relative upward slipping on the flanges 25 byindenting their flanges 4| or by pinching portions thereof inwardlyagainst the leg, for example, as has been shown at in Figs. 5 and '6. Toinsure that each leg may be held extended a length equal to that of theothers, and to make possible an easy determination of that length, thelegs are graduated by marks :at half-inch intervals along their lower'end portions as shown at 5| in Fig. 6.

After the legs 4|! have thus been assembled with the firebox housingsections, the bottom plate 32 is placed in the housing and pushed intoplace against the supporting flanges 30 as in Fig. 3, where it will beheld by the bosses 34.

The front panel 22 which has no inturned flange at its lower edge isthen adjusted up or down to brin the opening 23 therein to a properlevel for reception of the burner blast tube 16. With the fireboxapproximately in position in the furnace, the blast tube ['6 is extendedthrough housing l5 into the plate opening 23 as shown best in Fig. 3.The entrance to housing I5 is then bricked in about the blast tube, asshown at 58. i

In order that the firebox may be held in place, I then extend anchorstraps 58 along opposite sides of the blast tube and anchor them attheir inner ends in the plate slots 24-24 as at 6| in Fig. 2, and attheir outer ends turn them back over the outer end edge of a sleeve thatis applied about the blast tube to retain a heat insulating material.

This firebox construction makes possible the partial assembly of partsoutside the furnace, and their passage into the furnace through thedoorway, for final assembly by reaching through the doorway. Thus, thefirebox may be readily applied to alread existing furnaces without anymaterial trouble.

The particular advantages of this type of stainless steel fireboxconstruction, aside from cost, reside in the long life of the structure;the fact that the steel allows the firebox to attain its peaktemperature quickly and to radiate heat from its sides and bottom to thefurnace walls. By its 5 use, fire brick linings are eliminated, thusgiving additional radiating surface in the furnace.

Having thus described my invention, what I claim as new therein, anddesire to secure by Letters Patent, is:

1. A firebox structure of the character described comprising a pluralityof rectangular wall forming sections of sheet metal adapted to be joinededge to edge, by vertical joints, to form a substantially cylindricalhousing; each of said wall forming sections being formed with alongitudinal bead parallel with and adjacent each vertical edge andhaving each edge formed in a back-turned hook-like flange parallel tosaid bead, and leg-forming strips, with their opposite, longitudinaledges turned back in hook-like flanges, applied to the adjacent edgeflanges of adjoining sections in a slip joint assembly and disposedbetween the beads of the joined sections, said leg-forming strips beinglongitudinally adjustable and adapted to be extended below the loweredges of assembled sections as supporting legs for the said fireboxstructure and a bottom Wall fitted in the base of said housing and someof the side wall sections having inturned flanges at their lower edgesfor support of said bottom wall.

2. A firebox structure comprising a plurality of rectangular side wallforming sections of refractory sheet metal, each with its vertical edgesformed in back turned hook-like flanges, and leg forming members withopposite longitudinal edges turned back in hook-like flanges, applied tothe edge flanges of adjoining sections in a slip joint assembly, andadjustably extended below the lower edges of the assembled sections toserve as supporting legs for the structure; the opposite side sectionsof the structure having inturned flanges at their lower edges, and abottom wall applicable to the firebox as provided by the assembledsections, through its open upper end and supported on said inturnedflanges, to close the lower end of the firebox and to retain it in apredetermined shape.

CARL E. SCHINMAN.

REFERENCES CITED The following references are of record in the of thispatent:

UNITED STATES PATENTS Number Name Date 1,016,390 Beadle Feb. 6, 19121,757,664 Gohmann May 6, 1930 1,959,035 Noble May 15, 1934 2,240,367Fernholtz Apr. 29, 1941 2,244,314 Powers June 3, 1941 2,299,154 LairOct. 20, 1942 2,329,920 Loveley Sept. 21, 1943

